JPH0120662B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel and useful resin composition for room-temperature curable coatings, and more specifically, it contains a hydrolyzable silyl group and a monoester of a polymerizable unsaturated dibasic acid as essential characteristic groups. A pigment dispersion comprising a vinyl polymer containing a group derived from the silyl group, and a catalyst for condensing the silyl group through hydrolysis (hereinafter abbreviated as "hydrolysis-condensation"). The present invention relates to a composition which has excellent properties and which, upon curing, provides a coating film having excellent gloss and image clarity. In recent years, as part of energy saving measures in the paint field, the development of room temperature curing paints has been actively and multifaceted. Under these circumstances, polyurethane paints that use polyisocyanate as a curing agent have excellent curing properties at room temperature, and have come to be used for a variety of purposes because they provide coatings with excellent physical properties and appearance. . However, such urethane-based paints have problems with toxicity due to the raw material isocyanate.
In addition, it has the disadvantage that the coating film turns yellow in a short period of time, especially when used as a clear coating. On the other hand, paints that do not have this problem and use vinyl polymers with hydrolyzable silyl groups in their side chains as a base resin have been proposed, but due to poor pigment dispersibility, pigments such as titanium oxide cannot be used. When used as a colored paint, the coating film has the disadvantage of poor gloss and image clarity. In order to improve these drawbacks, a small amount of unsaturated monobasic acids such as acrylic acid and methacrylic acid or unsaturated dibasic acids such as maleic acid and fumaric acid are used as copolymerization components to introduce carboxyl groups into the base resin. Although the gloss and sharpness of the coating film are improved, a new drawback has been brought up in that the base resin significantly thickens during short-term storage, and this is a major unresolved problem in practical use. However, as a result of intensive studies in view of the above-mentioned deficiencies in the prior art, the present inventors found that an unsaturated dibasic acid monoester was incorporated into the main chain of the base resin as a repeating unit of the main chain. The present inventors have now completed the present invention by discovering that when the derived groups are introduced, the increase in the viscosity of the base resin is extremely small and a colored coating film with excellent gloss and image clarity can be obtained. That is, the present invention contains a hydrolyzable silyl group in the side chain and/or the terminal, and as a repeating unit of the main chain, the general formula [] as described below,
A vinyl polymer (A) which also contains a group derived from at least one polymerizable unsaturated dibasic acid monoester represented by [ ] and [ ] and the hydrolysis-condensation catalyst (B) for the silyl group are essential. To provide a resin composition for a room-temperature curable coating comprising as a component of the present invention. Here, the above-mentioned "hydrolyzable silyl group" introduced into the vinyl polymer (A) as a functional group for crosslinking refers to the general formula [However, R ¹ in the formula is an alkyl group, an aryl group,
A monovalent organic group such as an aralkyl group or a hydrogen atom, R ² is an alkoxy group, an acyloxy group, a phenoxy group, an alkenyloxy group, an iminooxy group,
It represents an amino group, a mercapto bond, or a halogen atom, and n is an integer of 0.1 or 2. ] Refers to at least one easily hydrolyzed functional group selected from the group consisting of an alkoxysilyl group, an acyloxysilyl group, a phenoxysilyl group, an alkenyloxysilyl group, an iminooxysilyl group, a mercaptosilyl group, and a halogenosilyl group. be. Among these silyl groups, it is most preferable to introduce an alkoxysilyl group since it does not produce undesirable volatile components during curing. In order to introduce an alkoxysilyl group into the vinyl polymer (A), a mixture of a vinyl monomer containing an alkoxysilyl group and another vinyl monomer copolymerizable with the monomer is used. radical polymerization of a vinyl monomer using an alkoxysilane containing a mercapto group as a chain transfer agent, or a separately prepared vinyl polymer having an unsaturated group or an epoxy group in its side chain. Well-known methods such as reacting with aminosilanes, hydrosilanes, or mercaptosilanes containing alkoxysilyl groups can be applied, but the simplest method is to use one or both of these, or a combination of and. be. Specific examples of vinyl monomers containing alkoxysilyl groups used when introducing alkoxysilyl groups by the above copolymerization method include γ
-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxypropylmethyldimethoxysilane,
Examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris(β-methoxyethoxy)silane, and allyltrimethoxysilane. Specific examples of the alkoxysilane containing a mercapto group used when introducing an alkoxysilyl group by the above method using a chain transfer agent include γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane. For each of the alkoxysilyl group-containing monomers and/or mercapto group-containing alkoxysilanes described above, the amount of alkoxysilyl groups introduced per 1000 g of resin solid content is determined from the viewpoint of curability and stability.
It is preferred to use amounts ranging from 0.1 to 1 mol. The bond derived from the polymerizable unsaturated dibasic acid monoester introduced into the vinyl polymer (A) as one of the repeating units of the main chain has the following general formulas [], [] and [] Preferably, it is at least one selected from the group consisting of: That is, the general formula [However, R in the formula represents a cycloalkyl group, an aralkyl group, or an alkyl group substituted with a linear or branched alkyl group or a group having an oxygen atom or a nitrogen atom, respectively. ] In order to introduce such unsaturated dibasic acid monoester units into the above-mentioned vinyl polymer (A), ○a. (b) Copolymerizable unsaturated dibasic acids or their acid anhydrides are copolymerized with vinyl monomers copolymerizable with them, and alcohols or Well-known methods such as monoesterification by reacting a monoepoxy compound can be applied. First, the monoesters of polymerizable unsaturated dibasic acids used when introducing by the method of ○A above include unsaturated dibasic acids such as maleic acid, fumaric acid, or itaconic acid, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, 2-ethylhexanol, n-octanol, lauryl alcohol, cyclohexanol, benzyl alcohol, 2-ethoxyethanol, 2-butoxyethanol or N, Monoesters with monohydric alcohols such as N-dimethylaminoethanol; or monoesters of the unsaturated dibasic acids with ethylene oxide, propylene oxide, butylene oxide, butyl glycidyl ether, phenyl glycidyl ether, glycidyl benzoate, glycidyl versatate, etc. and a monoepoxy compound in a molar ratio of 1:1. These may be used alone or as a mixture of two or more. Next, in order to introduce it by the method of (○) and (b) above, an unsaturated dibasic acid such as maleic acid, fumaric acid, or itaconic acid or an acid anhydride thereof is copolymerized, and the polymerization is carried out during or after the polymerization reaction. Afterwards, monoesterification may be effected by reacting with a monohydric alcohol or a monoepoxy compound as described above. In this case, in order to prevent significant thickening or gelation during polymerization, it is preferable to carry out monoesterification during the polymerization reaction, and this method is recommended. In this way, the bonds derived from the unsaturated dibasic acid monoester introduced into the vinyl polymer (A) described above can be applied to the solid content of the vinyl polymer from the viewpoint of pigment dispersion effect and storage stability. It is preferable to introduce it into the polymer (A) so that the acid value is in the range of 2 to 20. The alkoxysilyl group-containing vinyl monomer and/or mercapto group-containing alkoxysilane as described above, and a monomer for introducing an unsaturated dibasic acid monoester unit are copolymerized with a vinyl monomer copolymerizable with these. The base resin component of the present invention can be obtained by copolymerization. Typical examples of such copolymerizable vinyl monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and benzyl (meth)acrylate. (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate; hydroxyalkyl esters of (meth)acrylic acid such as maleic acid, fumaric acid or itaconic acid; Dialkyl esters of basic acids; aromatic vinyl compounds such as styrene, α-methylstyrene or vinyltoluene; also vinyl acetate, vinyl chloride, acrylonitrile, methacrylonitrile, N,N-dialkylaminoalkyl methacrylate, acrylamide, methacrylamide or N-alkoxymethyl (meth)acrylamide. The vinyl polymer (A) described above can be prepared by any known method such as solution, bulk or suspension polymerization, but solution radical polymerization is most preferred. Typical solvents used in this process include hydrocarbons such as toluene, xylene, cyclohexane, n-hexane, and octane; methanol, ethanol,
Alcohols such as i-propanol, n-butanol, i-butanol, sec-butanol, and ethylene glycol monoalkyl ether; esters such as ethyl acetate, methyl acetate, butyl acetate, or acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Although there are ketone solvents, in order to prevent significant thickening and gelation during polymerization, and to improve the storage stability of this vinyl polymer (A) solution and the pot life of the composition of the present invention, the total amount of solvent is It is preferable that at least 10% by weight of the above-mentioned alcohol solvent be used. Polymerization may be carried out by a conventional method using such a solvent and a polymerization initiator such as an azo type or peroxide type polymerization initiator. In addition, during polymerization, lauryl mercaptan, 2-mercaptoethanol or α
- Chain transfer agents such as methylstyrene dimer can also be used. Typical examples of the curing catalyst (B) for hydrolyzing and condensing silyl groups used in the present invention include butylamine, dibutylamine, hexylamine, t-
Basic compounds such as butylamine, ethylenediamine, triethylamine, isophoronediamine, imidazole; tetraisopropyl titanate,
Tetrabutyl titanate, tin octylate, lead octylate, cobalt octylate, zinc octylate,
Metal-containing compounds such as calcium octylate, lead naphthenate, cobalt naphthenate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin malate; p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid , dialkyl phosphoric acid, phosphate ester of β-hydroxyethyl acrylate, monoalkyl phosphorous acid, dialkyl phosphorous acid, etc., but especially dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, and dibutyltin diacetate. Tin compounds such as tin malate are preferred. The amount of these catalysts (B) used is 0.001 to 10% by weight, preferably 0.01 to 5% by weight based on the solid content of the polymer (A).
Weight%. The composition of the present invention thus obtained can be used as a clear paint in the same way as conventional paints, but it can be used as a colored paint by blending inorganic pigments such as titanium oxide, organic pigments, dyes, etc. Features are demonstrated. In addition, the composition of the present invention may also contain additives such as known flow regulators, color separation inhibitors, silicates, silane coupling agents, and cellulose derivatives such as nitrocellulose and cellulose acetate butyrate. be able to.
Specific examples of the above silicates and silane coupling agents include methyl silicate, ethyl silicate, butyl silicate, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ -Methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, etc. As the solvent used in the composition of the present invention, the above-mentioned ones can be used, but from the viewpoint of pot life, it is preferable to use an alcoholic solvent in an amount of at least 10% by weight of the total solvent. When preparing a colored paint, the above-mentioned coloring agent can be added to component (A), and coloring can be carried out using a well-known dispersion device such as a paint conditioner, roll mill, or ball mill. The paint obtained from the composition of the present invention can be applied to an object to be coated by a conventional method and dried at room temperature for several days to obtain a cured film with excellent gloss and sharpness. It may be cured by baking for 10 to 30 minutes. The composition of the present invention can be used for coating automobile repair, woodwork, building materials, plastics, etc., for which urethane-based paints have conventionally been used. Next, the present invention will be explained in detail with reference to Examples, in which parts and % refer to parts by weight and % by weight. Reference Example 1 [Preparation example of vinyl polymer (A)] 200 parts of toluene and 400 parts of n-butanol were charged into a reactor equipped with a stirrer, a thermometer, a cooling tube, a nitrogen introduction tube, and a dropping funnel, and nitrogen was added. The temperature was raised to 80°C under atmosphere. Next, 300 parts of styrene,
200 parts of methyl methacrylate, 250 parts of butyl methacrylate, 126 parts of n-butyl acrylate,
γ-methacryloxypropyltrimethoxysilane
100 parts, monobutyl maleate 24 parts, azobisisobutyronitrile 20 parts, t-butylperoxy-
10 parts of 2-ethylhexanoate and toluene
A mixture of 400 parts was added dropwise over a period of 3 hours. After that, it is kept at the same temperature for 15 hours to reduce the non-volatile content to 50%.
an alkoxysilyl group with a number average molecular weight of 10,000, a Gardner viscosity IJ and an acid value of 7.8 in solid content;
and a bond derived from monobutyl maleate (hereinafter, this will be abbreviated as polymer (A-1)) solution was obtained. Reference Example 2 [Same as above] The non-volatile content was 51 in the same manner as in Reference Example 1, except that 14 parts of maleic anhydride was used instead of monobutyl maleate, and the amount of n-butyl acrylate was 136 parts. %, viscosity J, number average molecular weight
10,000 and a solid content acid value of 7.9, a solution of a vinyl polymer containing an alkoxysilyl group and a bond derived from monobutyl maleate was obtained.
Hereinafter, this polymer will be abbreviated as polymer (A-2). Reference Examples 3 and 4 [Same as above] Derived from an alkoxysilyl group with a number average molecular weight of 10,000 and an unsaturated dibasic acid monoester in exactly the same manner as Reference Example 1, except that the monomers specified in Table 1 were used. A vinyl polymer containing a bond was obtained. Hereinafter, these polymers will be abbreviated as polymers (A-3) and (A-4), respectively. Reference Example 5 [Example of preparation of vinyl polymer for comparison] In a reactor similar to Reference Example 1, 200 parts of toluene,
400 parts of n-butanol and 2 parts of fumaric acid were charged, and the temperature was raised to 80°C under a nitrogen atmosphere. Next, 300 parts of styrene, 200 parts of methyl methacrylate, 242 parts of butyl methacrylate, butyl acrylate
150 parts, γ-methacryloxypropyltrimethoxysilane 100 parts, azobisisobutyronitrile 20 parts
10 parts of t-butylperoxy-2-ethylhexanoate and 400 parts of toluene were added dropwise over 3 hours. One hour and two hours after the start of the dropwise addition, 4 parts and 2 parts of fumaric acid were added, respectively. After that, it was kept at the same temperature for 15 hours, and the nonvolatile content was 50%, the number average molecular weight was 10,000, and the viscosity was I-
J. A solution of a vinyl polymer containing an alkoxysilyl group and a bond derived from fumaric acid and having an acid value of 7.7 in solid content was obtained. Hereinafter, this will be abbreviated as polymer (A'-1). Reference Examples 6 to 8 [Same as above] A bond derived from acrylic acid or a bond derived from acrylic acid or methacrylic acid was prepared in exactly the same manner as Reference Example 1 except that the monomers specified in Table 1 were used. Vinyl polymers (A'-2) and (A'-3) having the derived bonds, and a vinyl polymer (A'-4) having only alkoxysilyl groups and no carboxyl groups were obtained. Ta. When we conducted storage stability tests on various vinyl polymers prepared in this way, we found that, as shown in Table 1, compared to polymers copolymerized with acrylic acid, methacrylic acid, or fumaric acid, It has been revealed that polymers containing bonds derived from unsaturated dibasic acid monoesters show very little thickening and have excellent storage stability. Example 1 100 parts of the polymer (A-1) obtained in Reference Example 1,
Glass beads of 1 mm diameter were added to a mixture consisting of 50 parts of "Tiepeke R-820" (rutile type titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) and 16.6 parts of a mixed solvent of toluene/n-butanol = 70/30 (weight ratio). In addition, 2 coats of paint conditioner manufactured by Red Devil Co., Ltd.
A white base was obtained after shaking for an hour. Next, 0.3 parts of dibutyltin diacetate was added to 100 parts of this white base to obtain a white paint having a PWC of 50%. After that, this white paint was mixed with toluene/n.
- It was diluted with a butanol mixed solvent, sprayed on a zinc phosphate treated steel plate, and then dried at 23° C. for 3 days to obtain a white coating film with a thickness of about 50 μm. The gloss and sharpness of the coating film thus obtained were good as shown in Table 2. Examples 2 to 4 and Comparative Example 1 After repeating the same operation as in Example 1 using the vinyl polymer shown in Table 2 and "Tiepeque R-820" to obtain a white base, dibutyltin diacetate was added. A white paint with a PWC of 50% was obtained. Thereafter, the results of the performance of the coating films obtained by the same operations as in Example 1 using the various coating materials thus obtained are shown in the same table.

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Claims (1)

[Scope of Claims] 1 Contains a hydrolyzable silyl group in the side chain and/or terminal, and has at least one of the following general formulas [], [], and [] as a repeating unit of the main chain. The vinyl polymer (A) also contains bonds derived from two polymerizable unsaturated dibasic acid monoesters, and the catalyst (B) for hydrolysis and condensation of the silyl group as essential components. Resin composition for room temperature curable paint. Record [However, R in the formula represents a cycloalkyl group, an aralkyl group, or a linear or branched alkyl group or an alkyl group substituted with a group having an oxygen atom or a nitrogen atom, respectively. ]